Offline power supply and apparatus for charging a plug-in vehicle / Lear Corporation

Title: Offline power supply and apparatus for charging a plug-in vehicle.Abstract: An offline power supply includes a power supply circuit including a primary-side circuit for connecting to a first power source, a secondary-side circuit for connecting to a load, and a transformer connecting the primary-side circuit and the secondary-side circuit. A switch operates to selectively connect the primary-side circuit to the first power source. A second power source is charged during operation of the power supply circuit. A controller powered by the second power source has at least one input, and an output to selectively operate the switch based on the at least one input. ...

TECHNICAL FIELD

BACKGROUND

Existing, standard low-power plug-in chargers are made by many manufacturers and are in widespread use. These chargers have no automatic control to disconnect the transformer primary from AC power. These systems consume energy as long as they are plugged in, whether or not the system is operating.

More generally, existing power supplies result in parasitic non-operating energy waste. An off-line power supply continues to consume energy as long as the system is plugged-in, even when the system for which power is being supplied is not operational, such as when the system is off, battery is fully charged, etc.

Examples of such systems include power supplies for laptop computers, plug-in battery chargers for hand-held electronic devices such as cell phones, portable music players. Any “instant on” device that responds to remote control units, such as television sets, cable boxes, also continues to consume energy even when the unit is turned off. This is necessary to allow the unit to be able to respond to the remote control signal.

Put another way, as long as there is an AC transformer plugged into the AC power source, the unit will consume energy. The only way to stop this parasitic power consumption is to remove the AC power source. Removing the AC power source usually requires unplugging the unit from the AC socket. This may be an inconvenience and many users leave units plugged in all the time, resulting in considerable waste of energy when considered across the distribution of households on a continual basis.

An existing high power (200-400 VDC) charger has a switch (transistor) on the primary side of the transformer for control. Since a control signal is necessary to activate this switch and energize the transformer, the system requires an existing battery charge to be present in order to initialize the charger system operation.

Background information may be found in U.S. Pat. Nos. 7,894,212, 6,445,268, 6,198,638, 5,390,101, 6,061,257, and 7,295,449. Further background information may be found in U.S. Pub. Nos. 2003/0210118, 2008/0061746, 2006/0062027.

SUMMARY

In one embodiment, an offline power supply comprises a power supply circuit including a primary-side circuit for connecting to a first power source, a secondary-side circuit for connecting to a load, and a transformer connecting the primary-side circuit and the secondary-side circuit. A switch operates to selectively connect the primary-side circuit to the first power source. A second power source is charged during operation of the power supply circuit. A controller powered by the second power source has at least one input. The controller generates an output to selectively operate the switch based on the at least one input. A voltage isolation mechanism is preferably located between the output generated by the controller and the switch.

It is appreciated that embodiments of the invention may be implemented in a variety of ways. For example, the second power source may be a capacitor. Various controller inputs are possible. The controller may include a periodic wake up input to cause the periodic selective operation of the switch to charge the capacitor. One way to implement the periodic wake up input, when the second power source is a capacitor, is by making the periodic wake up input a connection to the capacitor to monitor the charge of the capacitor. As well, the controller may include one or more trigger inputs, such as a trigger input for monitoring the load. A trigger input for monitoring the load may be implemented as a connection to the secondary-side circuit to sense a load current.

In another possible feature, an embodiment of the invention may include a manual bypass switch operable to selectively connect the primary-side circuit to the first power source to thereby charge the second power source. An interlock mechanism may be associated with the manual bypass switch to allow for a continuous manual bypass.

It is appreciated that the invention involves many different features. These features may be implemented individually, or in various combinations as appropriate for a particular application of the invention. For example, a periodic wake up input, when included, may or may not be directly connected to the second power source. As well, one or more trigger inputs may be included, and controller operation in response may vary depending on the trigger event.

In another embodiment, an apparatus, cord-set, or wall-station for charging a plug-in vehicle is provided. The apparatus comprises a power supply circuit including a primary-side circuit for connecting to a first power source, a secondary-side circuit for connecting to the vehicle, and a transformer connecting the primary-side circuit and the secondary-side circuit. A switch operates to selectively connect the primary-side circuit to the first power source. A second power source is charged during operation of the power supply circuit. A controller powered by the second power source has at least one input. The controller generates an output to selectively operate the switch based on the at least one input. The at least one input includes a periodic wake up input to cause the periodic selective operation of the switch to charge the second power source. The periodic wake up input is a connection to the second power source to monitor the charge of the second power source. The at least one input includes a trigger input for monitoring the connection to the vehicle.

DETAILED DESCRIPTION

As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.

In accordance with an embodiment of the invention, an intelligent offline power supply can detect that there is negligible operating current and as a result can disconnect the primary side of the AC transformer. This has the same effect as un-plugging the power supply from the AC power source. When the AC source is disconnected, the power supply ceases to consume energy. When system operation current draw is detected by the controller, the AC power source is reconnected thereby resuming normal operation of the transformer.

In this embodiment, the controller itself runs from voltage stored in a super or high-efficiency capacitor that is charged when the transformer is operating normally. If the operational voltage of the capacitor falls below a threshold level, the controller re-connects the AC power source long enough to re-charge the capacitor. In an example implementation, re-charging may be completed within several seconds. After the capacitor is recharged, the AC power source is again disconnected by the controller. The capacitor voltage, in some embodiments, is less than 60 V.

At the more detailed level, a bypass switch may be provided to allow for the initial charging of the capacitor, thereby enabling the controller. The switch also allows for the system restoration if the capacitor ever completely discharges. In some implementations, a mechanical interlock may allow the user to permanently bypass the shutoff controller, making the system behave as a normal system without the disconnect feature.

It is appreciated that embodiments of the invention have many applications. For example, embodiments of the invention may be suitable for all low-power products that use a plug-in charger; or offline power supplies and consumer electronics devices that maintain some minimal level of operation in their off state. In particular, embodiments of the invention may be suitable for battery charging products such as the charger cord set for plug-in hybrid vehicles. And in general, embodiments of the invention may be suitable for all commercial chargers in which a transformer may be normally left plugged in.

FIG. 1 illustrates a block diagram of an offline power supply in an embodiment of the invention. The offline power supply is generally indicated at 10. An AC power source 12 supplies power at AC power source plug 14. The power supply circuit includes a primary-side circuit 16; the primary-side circuit 16 includes connection 18 for connecting to AC power source plug 14.

The power supply circuit further includes a transformer 20. The transformer 20 includes a primary winding 22 and a secondary winding 24. The power supply circuit further includes a secondary-side circuit 30 for connecting to a load. Transformer 20 connects primary-side circuit 16 and secondary-side circuit 30.

It is appreciated that transformer 20, rectifier 40, and step down and regulation circuit 44 may be implemented in any suitable way, as appreciated by one of ordinary skill in the art. Embodiments of the invention are not limited to any particular power supply topology.

With continuing reference to FIG. 1, a switch 50 is operable to selectively connect the primary-side circuit 16 and transformer 20 to the AC power source 12. In addition, a manual reset/bypass switch 52 is provided. The manual bypass switch 52 allows selective connection of the primary-side circuit 16 and transformer 20 to the AC power source 12 by a user; switch 50 is controlled by switch control signal 54. On the other hand, switch 52 may be manually operated.

As well, switch 52 preferably includes a mechanical interlock mechanism to allow for a continuous manual bypass. Switch 50 itself may be implemented in any suitable way, such as a transistor, as appreciated by one of ordinary skill in the art. As well, manual reset/bypass switch and mechanical interlock 52 may be implemented in any suitable way as appreciated by one of ordinary skill in the art.

In accordance with the invention, the offline power supply includes a second power source. The second power source is a dedicated power source, separate from the load. For example, in a low-power battery charger application, the second power source is separate from the battery being charged. In the particular example implementation of FIG. 1, the second power source takes the form of capacitor 60. Capacitor 60 is charged during operation of the power supply circuit.

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20121213|20120314462|offline power supply and charging a plug-in vehicle|An offline power supply includes a power supply circuit including a primary-side circuit for connecting to a first power source, a secondary-side circuit for connecting to a load, and a transformer connecting the primary-side circuit and the secondary-side circuit. A switch operates to selectively connect the primary-side circuit to the |Lear-Corporation